Gueri & Fred's astronomy
The page sums a test I have made to determine which instrument I shall use to achive the maximun resolution with a minimun size (to fit a 5kg tripod).
The constraints were :
weight : less than 3 Kg (with camera)
field with a 35 mm camera : more than 2° in it's wider side.
Therefore, I have tested : the MTO, the FS-60 and a catadioptric 600.
The test was made using a F 90x and a single T-Max 100. As bench card, "chasseur d'images" 's card were used.
As the goal of this test was to compare theses lens. The distance between the lens and the card was unchanged.
The distance recommended was 20 x focal length. The smaller lens was 355 mm so the distance should more than 7m. But the longer lens was 1m, so the distance should less than 20m.
Actual distance was about 12m.Field sample : On Feb 18th 2006
Sigma 600 :
FS-60 and sigma 600 are really close. The MTO is really better.